So day before last my motor started to have a tapping/knocking/vibration noise. It always occurs around 3000 rpm in the rear passenger side of the motor. I got a few opinions on it, one being that a camshaft sensor may be out, the other is that it wants to throw a rod. There aren't any check engine lights or anything on at all. The fix for one is a new sensor and use mid grade for a while (can sometimes help, idk why though). And the other is just get a new motor. Has anyone else had this come up? What was it for you and did you fix It? Any and all help is greatly appreciated. Thanks so much!

The first diagnosis should be to remove the serpentine belt, then run the engine briefly. This will immediately tell you if the problem is internal or if it is something on the accessory drive like the tensioner/alternator/water pump etc.

How many miles/km on cars? Remove belt as jayoldschool said and see if noise goes away but do not engine more than 1 minute as it will over heat. When was the last time you had the valve clearances checked? It could be a bad timing chain tensioner, worn out timing chain guides. Is the noise still there when engine is running with no load on it and car is not moving?

It just turned barely over 170k miles. I turned it in and tried the unplug injectors trick. I think it could be rod knock. Has anyone had rod knock? Did you have to replace the whole motor or were you able to just replace the bearings and everything ended up fine? I'm still gonna have a professional look at it. But if it is something too costly I'll just part it out.

If it is a rod making noise, the noise will go away or be reduces as the engine is under load and will be the loudest as the engine is freewheeling. In racing, most rods let go as the driver takes their foot off the gas pedal. When applying power, all the play in the rod is held tight but when the gas pedal is released that play loosens up, the noise gets loud and the rod comes apart. You should also see a drop in oil pressure when the engine is at idle.

If it is making noise, it is to late when it comes to a bad connection rod. The crankshaft journal will be worn egg shape and the new bearing insert will not fix that. The crankshaft will have to be ground and a under size bearing installed. Is the noise louder when the engine is cold or hot? Does the noise get louder as the engine is revving up or as it is revving down?

The bottom ends of these engines are pretty bullet proof. They don't wear out unless it has been over revved, not changing the oil, or ran out of oil. To blow one one these up on the lower end of the motor, you have to work at it. I am not saying it is impossible. There is not an engine made that can not be blown up. It is just that these motors don't make enough power to readily come apart at the lower end.